1. Field of the Invention
The present invention relates to a position detecting apparatus and method which are preferably used in e.g. a robot to position an object.
2. Description of the Related Art
In order to automatically supply water from the ground to a water tank mounted on a train, the following technique has been proposed. A robot is movably set in the neighborhood of a prescribed train stopping position, and a tube coupler for water supply attached to the working terminal of this robot is automatically connected with the tube coupler of the water tank mounted on the train to supply water to the water tank. An example of a position detecting method performing such a technique is as follows. Either one of the working terminals of the train and the robot is provided with a spot light source for emitting light therefrom. The other is provided with a semiconductor PSD (position sensing device), as available from Hamamatsu Photonics Limited at Hamamatsu city in Shizuoka, Japan, having a planar light receiving surface for detecting the two-dimensional position of the light emitted from the spot light source. Thus, the two tube couplers can be connected in a state that they are precisely positioned in a relationship from each other. However, this method has the following defects.
(1) Since the position is detected optically, detection error or detection impossibility may occur in poor environment.
(2) Power sources are required for both the light spot and the position detecting device. This is very disadvantageous since fewer power sources are preferable.